Fourier Transform Infrared Absorption Research Articles

Structure and Physical Properties of Borosilicate as Potential Bioactive Glasses

Borosilicate bioactive glasses containing titanium dioxide were prepared and investigated. The corrosion behavior of samples was examined for all samples upon immersion in phosphate solution. The erosion of the outer surface and ion exchange processes of the glass with the surrounding solution were studied by measuring the weight loss. Results were compared with samples that do not contain titanium dioxide. The final result of the reaction is the precipitation of hydroxyapatite. Characterization of the glasses was carried out by FTIR (Fourier transform infrared) absorption spectra before and after immersion in phosphate solution. The different crystalline phases and crystallographic parameters were explored using X-ray diffraction (XRD) analyzes and all indicate the precipitation of hydroxyapatite. A scanning electron microscope (SEM) is used to observe the morphological changes of the surfaces upon immersion. The atomic ratio of the final result product was obtained by the energy dispersive x-ray analysis (EDX) unit attached to the SEM. Changes in pH of the leaching solution were measured and evaluated. All measurements confirm that the studied glass has a high degree of biological activity which makes it very suitable for the field of biomaterials and other various medical applications.

Demodulation of multimodulation artifacts in Fourier-transform infrared spectroscopy.

Fourier-transform infrared (FTIR) spectra can show artifacts, for example, in the vicinity of the overtone when light is doubly modulated. Technical approaches, i.e., modifications to the spectrometer setup, have been devised in order to reduce those artifacts. Elimination of the artifacts was achieved only partly but at the expense of a loss of intensity or an increase in the noise level. We devised a computational demodulation scheme that is capable of almost fully reducing the artifacts with neither a loss of spectroscopic information nor an increase in the noise level. This has been demonstrated for the FTIR absorption spectra in the overtone regions of HCl(g) and CH4(g).

FTIR study of silicon carbide amorphization by heavy ion irradiations

We have measured at room temperature (RT) the Fourier-transform infra-red (FTIR) absorption spectra of ion-irradiated thin epitaxial films of cubic silicon carbide (3C–SiC) with 1.1 µm thickness on a 500 µm thick (1 0 0) silicon wafer substrate. Irradiations were carried out at RT with 2.3 MeV 28Si+ ions and 3.0 MeV 84Kr+ ions for various fluences in order to induce amorphization of the SiC film. Ion projected ranges were adjusted to be slightly larger than the film thickness so that the whole SiC layers were homogeneously damaged. FTIR spectra of virgin and irradiated samples were recorded for various incidence angles from normal incidence to Brewster’s angle. We show that the amorphization process in ion-irradiated 3C–SiC films can be monitored non-destructively by FTIR absorption spectroscopy without any major interference of the substrate. The compared evolutions of TO and LO peaks upon ion irradiation yield valuable information on the damage process.Complementary test experiments were also performed on virgin silicon nitride (Si3N4) self-standing films for similar conditions. Asymmetrical shapes were found for TO peaks of SiC, whereas Gaussian profiles are found for LO peaks. Skewed Gaussian profiles, with a standard deviation depending on wave number, were used to fit asymmetrical peaks for both materials. A new methodology for following the amorphization process is proposed on the basis of the evolution of fitted IR absorption peak parameters with ion fluence. Results are discussed with respect to Rutherford backscattering spectrometry channeling and Raman spectroscopy analysis.

Quantitative analysis of electronic absorption of phosphorus donors in diamond

In this work, phosphorus donors in diamond have been investigated by means of Fourier Transform Infra-Red (FTIR) transmission spectroscopy on a series of fully-characterized homoepitaxial layers. Low-temperature FTIR absorption spectra have been obtained for concentrations of donors in the range ND=3.7×1016–3.5×1018cm−3 and compensating acceptor impurities in the range NA=2.3×1016–3.0×1018cm−3. The absorption spectra is shown to exhibit two peaks at 4220cm−1 and 4540cm−1 corresponding to electronic transitions from the ground state to the 2p0 and 2p± excited states, respectively, of phosphorus donors in the neutral state of charge. The intensity of the most intense peak at 4540cm−1 is found proportional to ND-NA over two decades. The absorption cross-section of the corresponding transition is deduced providing a calibration law for the determination of ND-NA in phosphorus-doped diamond. Furthermore, the linewidth of the peak exhibits a linear variation with the compensating acceptor concentration, interpreted as the effect of the distribution of ionized impurities. The use of the non-destructive and contact-less FTIR optical method is finally discussed to determine the compensation ratio in phosphorus-doped diamond.

Optical properties of soda-lime-silica glasses doped with peanut shell powder

Purpose: Aim of this paper is to investigate the optical properties of soda-lime-silica (SLS) glasses which doped with different quantities of peanut shell (PS) powder.Design/methodology/approach: UV-Vis and Fourier transform infrared (FTIR) spectroscopy techniques are used to determine optical properties of glass.Findings: It was observed that the colorless and transparent pure SLS glass turned dark green in color with the addition of the PS powder. The glasses doped with PS powder contents 1 wt.% were translucent. The maximum absorption in the UV spectrum was observed at wavelengths of 306.20, 292.40, 280.20, and 303.20 nm for SLS glasses doped with PS powder contents of 0.5, 1, 3, and 5 wt.%, respectively. The UV-Vis spectroscopy results also indicated that the amount of light transmitted by the SLS glass decreased with increasing PS powder content. The FTIR absorption spectra of the PS powder-doped SLS glasses exhibited various bands corresponding to the symmetric and asymmetric stretching of the bridging oxygen atoms between the tetrahedra.Research limitations/implications: With the addition of the PS to the SLS glass, samples turned to dark green because of Fe2O3. Future researches must focus on this matter.Originality/value: PS powders are doped to investigate optical properties of glass. Thus, glasses, which have good properties such as economically cheap, bio-friendly, are produced from food wastes.

One-pot and green synthesis of Mn3O4 nanoparticles using an all-in-one system (solvent, reactant and template) based on ethaline deep eutectic solvent

Mn3O4 nanoparticles have been synthesized using a facile and sustainable method using ethaline (ethylene glycol–choline chloride) deep eutectic solvent (DES). The as-synthesized nanoparticles have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FTIR) spectroscopy, UV/vis absorption spectroscopy, and vibrating sample magnetometry (VSM). The XRD results point to crystallization of hausmannite Mn3O4 in tetragonal crystal structure with average crystallite size of 18 nm. The microscopy-elemental investigations suggest the synthesis of spherical nanoparticles with average particle size of 25 nm and high elemental purity. The obtained band gap of 3.4 eV for the as–synthesized Mn3O4 nanoparticles indicates the semiconductor nature of nanoparticles. FTIR absorption bands further confirm the formation of pure Mn3O4 nanoparticles. The magnetic characterization of as-synthesized Mn3O4 nanoparticles clearly reveals their paramagnetic behavior at room temperature. Based on our proposed mechanism the ethaline plays a triple role (solvent, reactant, and template) during the synthesis thereby it provides a green all-in-one system for synthesis, stabilization and better control over growth of Mn3O4 nanoparticles.

Characterization of Some Bioactive Glasses and Glass-ceramics Prepared by a Hydrothermal Method

Powders of different samples of bioactive silicate glass ceramics were prepared by a hydrothermal method (HTM). The thermal energy assisted method was applied as an alternative to ultrasonic and microwave energy radiation assisted tools. Characterization of the glasses was carried out by FTIR (Fourier transform infrared) absorption spectroscopy. The different crystalline phases and crystallographic parameters were explored using X-ray diffraction (XRD) analysis. Differential scanning calorimetry and thermogravimetric analysis were carried out to investigate the thermal characteristics of the prepared samples. Transmission electron microscopy (TEM) and electron diffraction patterns (EDP) were performed to examine the internal microstructure of the bioactive glass samples. The hydrothermal assisted method is an appropriate technique to carry out the reaction in a short time. In addition, this method can modify the reaction environment to produce amorphous glassy materials after just a short time of thermal treatment. The sintered glass-ceramic materials prepared by such technique are characterized with fine size and more crystallized structure than those prepared by the conventional melting method. Fine structure leads to an increase in surface area which in turn participates to a great extent in improving compatibility and bioactivity of the materials.

Comparative Characterisation of Closed and Active Landfill Composites Using EDX, FTIR and Proximate Techniques

The elemental and chemical constituents of an active and a closed landfill were compared using Fourier transform-infrared (FTIR) spectroscopy, scanning electron microscope/energy-dispersive X-ray spectroscopy, and proximate analysis. The two landfills had similar major elemental constituents representing 96.5 and 98.4 % of elemental composition for the closed (O > C > Si > Fe > Ca > Al) and active (C > O > Si > Al > Ca > Fe) landfill samples respectively. The average concentration of Al was significantly higher (p = 0.024) in the active landfill, while Ca was significantly higher (p = 0.023) in the closed landfill. Cluster analysis revealed that similarities were more influenced by the level of composite degradation (more degraded/less degraded) than by depth or seasonal variations. Samples from both landfills showed FTIR absorption peaks that indicated mineralisation and stability of waste constituent. Active landfill samples showed distinguishing peaks at 3690 and 3619 cm−1 attributed to O–H vibration of clayey mineral (kaolin), while closed landfill samples were characterised by a carbonates peak at 873 cm−1. For both landfills, the average ash content (>51 %) of the waste was above the level considered suitable for energy recovery from waste. These findings inform strategic decisions in management of the landfills and in the determination of possible alternative uses for landfill waste.

Effect of CuO2 planes on the structural and superconducting transport properties of [CuTl − 12(n − 1)n;n = 2,3,4] superconductor family

[Formula: see text] [Formula: see text] superconducting bulk samples have been synthesized by using two-step solid state reaction method. We investigated the effects of [Formula: see text] planes on the structural and superconducting transport properties of [Formula: see text] superconducting family. These samples were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) absorption spectroscopy and DC-resistivity [Formula: see text] measurements. These samples are [Formula: see text]-axis length oriented and have shown orthorhombic crystal structure. All the samples have shown metallic variations of resistivity from room temperature down to onset of superconductivity. The zero resistivity critical temperature [Formula: see text] increases with the increase in superconducting planes and normal state resistivity systematically decreases, which show the density of inadvertent defects decreases in the final compound. The apical oxygen phonon modes are hardened as observed in the FTIR absorption measurements. The intrinsic microscopic superconducting parameters, such as the cross-over temperatures, coherence length along [Formula: see text]-axis [Formula: see text] at 0 K, inter-layer coupling [Formula: see text], inter-grain coupling [Formula: see text] and fermi velocity [Formula: see text], were extracted from the fluctuation-induced conductivity (FIC) analysis. FIC analysis also showed the improvement in superconductivity with the increase in [Formula: see text] planes.

English

The surface composition and surface properties of water hyacinth (Eichhornia crassipes) root biomass were studied before and after extraction with dilute nitric acid and toluene/ethanol (2/1, v/v) followed by ethanol, using Fourier Transform Infra-red (FT-IR) spectroscopy, thermogravimetric analysis, x-ray diffraction, scanning electron microscopy. FT-IR absorption bands were obtained at 3421, 2855, 1457 and 1035 cm-1 (O-H stretch, C-H vibration, C-H asymmetric deformation, and C-O stretch, respectively) and 1508, 1541 and 1559 cm-1 (all aromatic skeletal vibrations characteristic of lignin), as well as a C=O carboxylate stretch vibrational band at 1654 cm-1. Scanning electron microscopy confirmed the root biomass to be amorphous and not to have a strongly structured surface. The dilute mineral acid and organic solvent treatment increased crystallinity. Thermogravimetric analysis Studies show that the treated biomass are more thermally stable than the untreated biomass. Data are presented showing that dilute mineral acid and organic solvent treatment resulted in a decrease in the amount of lignin in the biomass. The implications of the decrease in the percentage of lignin on the adsorption of volatile polar organic solvents and non-polar n-alkane hydrocarbons is discussed. Key words: Water hyacinth, biomass, surface composition, Fourier Transform Infra-red (FT-IR) spectroscopy, scanning electron microscopy, x-ray diffraction spectroscopy, thermo gravimetric analysis.

The evolution of dehydration and thermal decomposition of nanocrystalline and amorphous chromium hydroxide

Chromic oxide was synthesized through the dehydration and thermal decomposition of nanocrystalline and amorphous chromium hydroxide. The dehydration of amorphous chromium hydroxide had been researched clearly over the past few decades. Here, we mainly explored the different dehydration process between crystalline and amorphous chromium. The two samples were prepared by a simple one-step precipitation at 5°C and 25°C, and characterized using X-ray diffraction and high resolution transmission electron microscopy. The evolution of dehydration and thermal decomposition behaviors of the two samples were measured by derivative thermogravimetry and Fourier transform infrared (FT-IR) spectrometry. The dehydration of nanocrystalline chromium hydroxide occurred at 105°C, 289°C, and 409°C, whereas that of amorphous chromium hydroxide occurred at 70°C, 289°C, 406°C, and 443°C. At approximately 289°C, the actual quality of dehydration was only one water molecule, which was in agreement with the theoretical result (expressed as CrOOH). The FT-IR absorption bands at 3370 and 1620cm⿿1 gradually decreased in intensity with increasing annealing temperature and then finally disappeared at 600°C to become α-Cr2O3.

SPECTROSCOPIC ANALYSIS OF RHAMNOLIPID PRODUCED BY PRODUCED BY Pseudomonas aeruginosa UKMP14T

Biosurfactant produced by Pseudomonas aeruginosa UKMP14T was optimized by growing the isolate in mineral salt medium (MSM) supplemented with 1% (v/v) glycerol and 1.3 g/L ammonium sulphate with C/N ratio of 14:1. The culture medium was incubated at 37°C, with an agitation speed of 150 rpm for 7 days. P. aeruginosa UKMP14T produced biosurfactant at 0.8 g/L after 7 days incubation. Anthrone assay proved biosurfactant was glycolipid. The biosurfactant was characterized by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX) in addition to Fourier transform infra-red (FT-IR), nuclear magnetic resonance (NMR) and electrospray ionization-mass spectrometry (ESI-MS). The SEM-EDX analysis indicated the presence of carbon and oxygen elements by 78% and 22% (atomic %), respectively. FT-IR absorption spectra indicated the functional groups of rhamnolipid were located at 3308.46, 2922.91, 2857.09 and 1730.96 cm. ESI-MS/MS analyses identified P. aeruginosa UKMP14T produced rhamnolipid with two fatty acids-nine congeners, L-rhamnosyl-L-rhamnosyl-βhydroxydecanoyl-β-hydroxydecanoate (Rha-Rha-C10-C10) (m/z 649) which formed the main compound. The critical micelle concentration (CMC) of this rhamnolipid was established at 30 mg/L (32 dynes/cm). The characteristics of biosurfactant produced by P. aeruginosa UKMP14T indicated it has a high potential in industrial dan bioremediation application.

Combustion Synthesized Europium Doped LaAI₁₁O₁₈ Phosphors--An Electron Paramagnetic Resonance and Optical Study.

By adopting a facile solution combustion synthesis, crystallized europium doped blue phosphors were successfully prepared. These phosphors were characterized by X-ray diffraction (XRD), Fourier transform infrared absorption (FT-IR), energy dispersive analysis of X-ray, Electron Paramagnetic Resonance (EPR) and Photoluminescence (PL) experimental methods. The photoluminescence spectrum indicates Eu²⁺ and Eu³⁺ ions in these phosphors. The band at around 442 nm is attributed to the spin-allowed 4f⁶5d¹ (2D) --> 4f⁷(⁸S₇/2) transition of Eu²⁺ ions. The sharp bands at 591 (⁵D₀ --> ⁷F₁) and 616 (⁵D₀ --> ⁷F₂) nm are attributed to the spin-forbidden transitions of Eu³⁺ ions. The EPR spectra of as-prepared and post-treated LaAl₁₁O₁₈:Eu phosphors exhibit signals characteristic of La²⁺ and Eu²⁺ ions. The number of spins, Gibbs energy, magnetic susceptibility, Curie constant and effective magnetic moment values were calculated and compared at 296 and 110 K.

Spectroscopic investigations of high-energy-density plasma transformations in a simulated early reducing atmosphere containing methane, nitrogen and water.

Large-scale plasma was created in gas mixtures containing methane using high-power laser-induced dielectric breakdown (LIDB). The composition of the mixtures corresponded to a cometary and/or meteoritic impact into the early atmosphere of either Titan or Earth. A multiple-centimeter-sized fireball was created by focusing a single 100 J, 450 ps near-infrared laser pulse into the center of a 15 L gas cell. The excited reaction intermediates formed during the various stages of the LIDB plasma chemical evolution were investigated using optical emission spectroscopy (OES) with temporal resolution. The chemical consequences of laser-produced plasma generation in a CH4-N2-H2O mixture were investigated using high resolution Fourier-transform infrared absorption spectroscopy (FTIR) and gas selected ion flow tube spectrometry (SIFT). Several simple inorganic and organic compounds were identified in the reaction mixture exposed to ten laser sparks. Deuterated water (D2O) in a gas mixture was used to separate several of the produced isotopomers of acetylene, which were then quantified using the FTIR technique.

The mid‐IR Absorption Cross Sections of α‐ and β‐NAT (HNO3 · 3H2O) in the range 170 to 185 K and of metastable NAD (HNO3 · 2H2O) in the range 172 to 182 K

AbstractGrowth and Fourier transform infrared (FTIR) absorption in transmission of the title nitric acid hydrates have been performed in a stirred flow reactor (SFR) under tight control of the H2O and HNO3 deposition conditions affording a closed mass balance of the binary mixture. The gas and condensed phases have been simultaneously monitored using residual gas mass spectrometry and FTIR absorption spectroscopy, respectively. Barrierless nucleation of the metastable phases of both α‐NAT (nitric acid trihydrate) and NAD (nitric acid dihydrate) has been observed when HNO3 was admitted to the SFR in the presence of a macroscopic thin film of pure H2O ice of typically 1 µm thickness. The stable β‐NAT phase was spontaneously formed from the precursor α‐NAT phase through irreversible thermal rearrangement beginning at 185 K. This facile growth scheme of nitric acid hydrates requires the presence of H2O ice at thicknesses in excess of approximately hundred nanometers. Absolute absorption cross sections in the mid‐IR spectral range (700–4000 cm−1) of all three title compounds have been obtained after spectral subtraction of excess pure ice at temperatures characteristic of the upper troposphere/lower stratosphere. Prominent IR absorption frequencies correspond to the antisymmetric nitrate stretch vibration (ν3(NO3−)) in the range 1300 to 1420 cm−1 and the bands of hydrated protons in the range 1670 to 1850 cm−1 in addition to the antisymmetric O–H stretch vibration of bound H2O in the range 3380 to 3430 cm−1 for NAT.

Vibration-reorientation dynamics, structural changes and its interrelation with the phase transition in polycrystalline [Cr(OC(NH2)2)6](BF4)3

Polycrystalline hexakis(urea-O)chromium(III) tetrafluoroborate possesses in the temperature range of 295–105K one solid–solid phase transition at TC≈255K. Analysis of the band shapes associated with the νas(CN) and δas(NH2) vibrational modes of the Fourier transform infrared absorption (FT-IR) spectra, registered in the temperature range of 295–10K, indicated existence of fast (τR≈10−12s) reorientational motion of the protons from NH2 groups belonging to OC(NH2)2 (urea) ligands, which does not suddenly change at TC. Moreover, splitting of the IR bands associated with the νas(NH), νs(NH) and νas(BF)F2/νs(CN) modes at TC indicated that this phase transition is associated with a change of crystal structure. Similar analysis of the Raman scattering bands (FT-RS), associated with the δs(FBF)E, νs(BF)A and νas(BF)F2/νs(CN) vibrational modes, indicated fast reorientation of the BF4− ions, which does not suddenly change at TC, and additionally confirmed structural character of this phase transition. Results obtained from vibrational spectroscopy measurements are compatible with that obtained by electron paramagnetic resonance spectroscopy (EPR) measurements in function of temperature, where rapid narrowing of the EPR line in the vicinity of the TC was observed.

Large-scale synthesis of nickel sulfide micro/nanorods via a hydrothermal process

Rhombohedral-phase NiS micro/nanorods were synthesized on a large scale through a hydrothermal method using NiCl2·6H2O and thiourea crystals as starting precursors. Recrystallized thiourea was observed to play an important role in the formation of micro/nanosized rods and flower-like structures. The molar ratio and reaction temperature of the precursors influenced the morphology and phase of NiS products. Pure rhombohedral NiS micro/nanorods were obtained on a large scale when the molar ratio between NiCl2·6H2O and thiourea crystals was fixed at 2:1, and the mixture was heated at 250°C for 5 h. Flower-like NiS nanostructures were formed when the molar ratio between NiCl2·6H2O and thiourea crystals was maintained at 1:1. The Raman and Fourier-transform infrared (FTIR) spectra of the as-prepared rhombohedral NiS micro/nanorods were collected, and their magnetic properties were investigated. The results showed that the FTIR absorption peaks of the as-prepared product are located at 634 cm−1 and their Raman peaks are located at 216 and 289 cm−1; the as-prepared NiS micro/nanorods exhibited weak ferromagnetic behavior due to the size effect.

Interactions of the Anticancer Drug Tamoxifen with Lipid Membranes

Interactions of the hydrophobic anticancer drug tamoxifen (TAM) with lipid model membranes were studied using calcein-encapsulated vesicle leakage, attenuated total reflection Fourier transform infrared (FTIR) spectroscopy, small-angle neutron scattering (SANS), atomic force microscopy (AFM) based force spectroscopy, and all-atom molecular dynamics (MD) simulations. The addition of TAM enhances membrane permeability, inducing calcein to translocate from the interior to the exterior of lipid vesicles. A large decrease in the FTIR absorption band’s magnitude was observed in the hydrocarbon chain region, suggesting suppressed bond vibrational dynamics. Bilayer thickening was determined from SANS data. Force spectroscopy measurements indicate that the lipid bilayer area compressibility modulus KA is increased by a large amount after the incorporation of TAM. MD simulations show that TAM decreases the lipid area and increases chain order parameters. Moreover, orientational and positional analyses show that TAM exhibits a highly dynamic conformation within the lipid bilayer. Our detailed experimental and computational studies of TAM interacting with model lipid membranes shed new light on membrane modulation by TAM.

Spatio-temporal evolution of the dust particle size distribution in dusty argon rf plasmas

An imaging Mie scattering technique has been developed to measure the spatially resolved size distribution of dust particles in extended dust clouds. For large dust clouds of micrometre-sized plastic particles confined in an radio frequency (rf) discharge, a segmentation of the dust cloud into populations of different sizes is observed, even though the size differences are very small. The dust size dispersion inside a population is much smaller than the difference between the populations. Furthermore, the dust size is found to be constantly decreasing over time while the particles are confined in an inert argon plasma. The processes responsible for the shrinking of the dust in the plasma have been addressed by mass spectrometry, ex situ microscopy of the dust size, dust resonance measurements, in situ determination of the dust surface temperature and Fourier transform infrared absorption (FT-IR). It is concluded that both a reduction of dust size and its mass density due to outgassing of water and other volatile constituents as well as chemical etching by oxygen impurities are responsible for the observations.

Spectroscopic studies of SiOx films irradiated with high energy electrons

The effect of 20 MeV electron irradiation on the vibrational properties of homogeneous SiOx films and SiOx films containing amorphous or crystalline Si nanoparticles is studied. Layers with x = 1.15 and 1.3 and two different thicknesses, 200 nm and 1000 nm, were deposited on crystalline silicon substrates and annealed at 250 °C for stabilization. No nanoparticle growth occurs at this temperature. A part of the films were annealed in an inert atmosphere at 700 °C or 1000 °C for 60 min in order to grow amorphous (a-Si) or crystalline (nc-Si) silicon nanoparticles, respectively. Samples from all types of the films were irradiated with 20 MeV electrons at close to room temperature and a fluence of 2.4×1014 el.cm−2. The effect of the irradiation was investigated by means of Fourier Transform Infrared Absorption (FTIR) and Raman scattering spectroscopy. The FTIR results show no appreciable changes in the composition of the homogeneous SiOx films and the oxygen content in the matrix of a-Si- SiOx composite films. The electron irradiation causes an increase of the intensity of the light scattered from the pure silicon phase. The results obtained are discussed in terms of disorder decrease in the Si nanoparticles stimulated by MeV electron beam irradiation.